Designing Solar Thermal Applications

Transcription

1 Designing Solar Thermal Applications Murat Aydemir Viessmann Middle East FZE General Manager (M.Sc. Mech.Eng., ASHRAE) Doha Green Conference Workshop The Moevenpick Towers and Suites, Doha

2 Viessmann Werke Founded: 1917 Headquarters: Allendorf (Eder) GER Products: Comprehensive product range heating- and climatetechnology Employees: Turn-over: 1,7 Bil. Euro Export Share: 60 % Third generation family-owned enterprise Among the Top 3 of industry

3 Viessmann Headquarter Allendorf (Eder), Germany 130 km North of Frankfurt

4 Comprehensive product range For all energy sources and all output ranges kw to 20 MW in three program levels 1,5 kw kw Oil Natural Gas Solar Bio Energy Natural Heat Energy sources: Output range: Range categories: System solutions: Oil, natural gas, solar, bio energy (wood, biogas), natural heat 1,5 kw to kw 100 Plus, 200 Comfort, 300 Excellence Integrated system components

5 The power source of the earth In less than four hours the sun radiates the annual energy demand of the world s population to the earth. Annual Solar Radiation on Earth Estimated Fossil Fuel Sources Annual Energy Consumption on Earth

6 Solar radiation on the Earth Atmosphere 1360 W/m W/m 2

7 Solar energy Annual energy amount (global radiation) Country City Annual energy amount kwh / m 2 x year UAE Dubai 2027 Qatar Doha 1990 Saudi Arabia Riyadh 1873 Jordan Amman 1870 Syria Damascus 1862 Lebanon Beirut 1734 Italy Milano 1241 France Paris 1127 Germany Frankfurt 1087 UK London 899

8 Solar radiation on the Earth Utilisation of solar energy in the collectors Output / losses A B C D E F G H K diffused radiation direct solar radiation wind, rain, snow, convection convection losses thermal conduction losses heat radiated by the absorber heat radiated by the glass cover useful collector output reflection -Diffuse radiation of Doha is 44,5 % Daily energy values irradiated onto the horizontal plane over a 12 month period

9 related to buildings Heat Electricity (direct with PV) Concentrated Solar Power Solar lighting Bio Fuels

10 Solar energy related to buildings What can we do with the heat? Heat - Domestic hot water - Pool heating - Heating support in cold climates - Process heat - Solar cooling with absorption chillers - Solar desalination >80%

11 Solar-thermal: Heat through sunshine Vitosol 100/200-F Flat Vitosol 200-T tube Vitosol 300-T tube-heat pipe

12 Vitosol 200-F Flat collector All round folded aluminium frame Stable, highly transparent cover made from special glass S patterned copper absorber Highly effective thermal insulation

13 Vitosol 200-T Evacuated tube collector with copper absorber, direct flow Highly effective thermal insulation Coaxial distributor pipe Header Direct flow Sol-titanium coated absorber High grade, low ferrous glass

14 Vitosol 300-T Evacuated tube collector with copper absorber, heat pipe technology Highly effective thermal insulation Dry connection, no direct contact between carrier and heat transfer medium High grade, low ferrous glass Duotec twin-pipe heat exchanger with integral overheating protection Heat pipe Sol-titanium coated absorber

15 Solar Thermal Collector efficiency Solar heating system for DHW Solar heating system for DHW and central heating back-up Solar heating system for generating process heat / solar air conditioning

16 Life expectations of solar collectors 20 years +

17 Life expactations of solar collectors 30 years 35 years

18 Certificates of solar collectors Performance & Reliability Test reports according to EN 12975

19 Solar thermal hot water generation

20 Design of a solar thermal system for DHW 1 Solar collectors, Vitosol 2 pumping station Divicon and accessories 1 3 Dual mode or multi mode DHW cylinder Control unit Vitosolic 5 Back-up system oil/gas boiler, electrical or heat pump

21 Design of a solar thermal system for DHW Planning data Basic information => For Solar: Daily consumptions => For Backup peak consumptions DHW cylinder volume Absorber surface area Pipe sizing Circulation pump (Solar Divicon) sizing Expansion vessel sizing Vitosol control unit

22 Design of a solar thermal system for DHW Planning data Location: Beirut Lebanon Roof characteristics Flat roof Direction towards south No of persons: 4 persons DHW temperature 60 o C Cold water temperature; Winter 10 o C Summer 20 o C Back-up system: oil boiler

23 Design of a solar thermal system for DHW Basic information Consumption A Room heating requirement of a building B Room heating requirement of a low-energy house C Hot water required Gain D Solar energy yield with 5 m² of absorber surface area E Solar energy yield with 15 m² of absorber surface area

24 Design of a solar thermal system for DHW Basic information The solar system has to be selected for the maximum energy level The solar system cannot cover 100% of the consumption Realistic value is % of annual energy demand

25 Design of a solar thermal system for DHW Sample: Buffer tank for solar thermal system l/pers/day Energy needs to be stored => Daily buffer

26 Design of a solar thermal system for DHW DHW cylinder volume Max 50 l/pers/day at 60 o C or 70 l/pers/day at 45 o C DHW temperature of 60 o C In our case: 4 pers x 50 l/pers/day = 200 l/day at 60 o C or 280 l/day at 45 o C => the cylinder capacity 400 l.

27 Design of a solar thermal system for DHW Absorber surface area Higher solar coverage Higher collector temperature Less collector efficiency

28 Design of a solar thermal system for DHW Absorber surface area Solar radiation ~1000 W/m2 If sun is shinning for 6 7 hours/day => Daily maximum gain 6 7 kwh/m2 The DHW temperature 60 o C/10 o C The DHW flow: 6/50 = 0.12 m3/(h x m2) (Check Meteorological data!!) 100 l of DHW at 60 o C per m 2 of collector In our case: 400 l/day / 100 l/m 2 = 4 m 2 => 2 collectors Vitosol 200F

29 Design of a solar thermal system for DHW Meteorological data for Doha

30 Design of a solar thermal system for DHW Pipe sizing Flow rate in the collector array: - The safe flow rate: - Vitosolic flat collectors 25 l/(h x m 2 ) - Vitosolic tube collectors 40 l/(h x m 2 ) - The maximum flow rate: - Vitosolic flat collectors 40 l/(h x m 2 ) - Vitosolic tube collectors 60 l/(h x m 2 ) Flow velocity: - do not exceed 1 m/s - recommended: 0.4 to 0.7 m/s

31 Design of a solar thermal system for DHW Pipe sizing

32 Design of a solar thermal system for DHW Pipe sizing In our case: 2 collectors x 2.3 m2 = 4.6 m2 Required flow rate 30 l/(h x m2) Total flow rate (collector area): 138 l/h = 2.3 l/min From the table, the pipe dimension will be DN10 (12x1) with a flow velocity of m/s

33 Design of a solar thermal system for DHW Circulation pump Solar Divicon

34 Design of a solar thermal system for DHW Circulation pump Solar Divicon The pump has to be selected according to the required flow rate and total pressure drop of the solar system which comprises of: - collector pressure drop - pipe work pressure drop - individual pressure drop values of the fittings - pressure drop of the internal indirect coil in the DHW cylinder A Pressure drop curve of Solar Divicon or solar pump line B Residual head

35 Design of a solar thermal system for DHW Circulation pump Solar Divicon Absorber area Specific flow rate in l/(h x m 2 ) m Low flow operation High flow operation Flow rate in l/min Use of type PS10 or P10, with a residual head of 150 mbar (1.5 m) Use of type PS20 or P20, with a residual head of 260 mbar (2.6 m)

36 Design of a solar thermal system for DHW Circulation pump Solar Divicon In our case: 2 collectors x 2.3 m2 = 4.6 m2 Required flow rate 30 l/(h x m2) We can use a Solar Divicon pump PS 10 with a flow rate of ~2.2 l/min. Absorber area Specific flow rate in l/(h x m 2 ) m Low flow operation High flow operation Flow rate in l/min

37 Design of a solar thermal system for DHW Expansion vessel The expansion vessel has to perform 2 basic tasks: - Maintaining the pressure at each point of the system within the admissible limits; - Compensation of the volume variations of the heating water due to temperature variation.

38 Design of a solar thermal system for DHW Expansion vessel Selection of an expansion vessel (subject to the collector type and in conjunction with a 6 bar safety valve). The details in the above tables are standard values. These values must be verified by appropriate calculation

39 Design of a solar thermal system for DHW Expansion vessel

40 Design of a solar thermal system for DHW Vitosol control unit Vitosolic Switching the solar circuit pump for DHW and/or swimming pool water heating - Electronic limiter for the temperature in the DHW cylinder (safety shutdown at 90 C) - Collector safety shutdown Solar DHW heating with a mono or a dual mode DHW cylinder

41 Design of a solar thermal system for DHW Vitosol control unit Vitosolic Switching the solar circuit pump for DHW and/or swimming pool water heating or other consumers (maximum of 4 differential temperature control) - Electronic limiter for the temperature in the DHW cylinder (safety shutdown at 90 C) - Collector safety shutdown

42 Design of a solar thermal system for DHW Large scale solar thermal system l/pers/day

43 Design of a solar thermal system for DHW Large scale solar thermal system l/pers/day Energy needs to be stored

44 Design of a solar thermal system for DHW Large scale solar thermal system l/pers/day The volume of the buffer tank can be approximated as follow: 50 l buffer tank per square meter of collector area

45 Thumb rules DHW demand: 50 l/pers/day at 60 o C Collector area: 1 m 2 at 100 l of DHW at 60 o C Buffer tank: 50 l/m 2 of absorber area

46 Solar simulation T Sol Solar simulation software

47 Solar simulation System design

48 Solar simulation Results of Annual Simulation

49 Solar simulation Solar energy consumption / Daily max collector temperature

50 Installation example Case study Green building Manchester

51 Installation example UAE Jebel Ali process heating system Solar absorber gross surface area : m 2 Energy produced by collectors : Diesel savings : CO 2 emissions avoided : 376,4 MWh/year 48,1 m 3 /year kg Application : Process heat for hot water loop at manufacturing plant

52 Installation example UAE Jebel Ali process heating system

53 Installation example UAE DHW system Shoreline Apartments Palm Jumeirah Solar absorber gross surface area: 14 x 200 m 2 (2800 m 2 ) Energy produced by collectors : Natural gas savings : CO 2 emissions avoided : 3805 MWh/year m 3 /year kg Application : DHW Backup system: Gas fired wall hung condensing boilers

54 Installation example UAE DHW system Shoreline Apartments Palm Jumeirah

55 Installation example UAE DHW system Shoreline Apartments Palm Jumeirah Viessmann Domestic Hot Water cylinders Viessmann Gas condensing boilers for the backup of the system (109 % efficiency)

56 Installation example UAE DHW system Villas in Jumeirah Solar hot water system with electric backup

57 Installation example UAE DHW system for labour camp in Al Quoz Dubai Operational since 2000

58 Questions?

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60 Solar energy needs good engineering design and installation to reach the goal! Together with the design of renewables check the energy saving potential! Saving + renewable = Target > 40 %

61 Vitocal 160-A Air source heat pump for DHW heating 1,52 kw, 285 liters Sample Calculation: 300liters/day hot water 1.Electrical heater Q = 300 x (60-10)/860 = 17,5 kw Daily loss 1 kw Electric consumption: 18,5 kw 2. Vitocal cylinder with heat pump Q = 18,44 kw required electricity 5,2 kw Cooling inside approx 17 kw Saving at the AC of housing 5,7 kw Electric consumption: 5,7-5,2 = - 0,5 kw SAVING = 18,5 +0,5 = 19 kw Annual expected saving 6840 kwh (Max connected electrical load 500 W)

62 Vitocal 160-A in combination with solar energy Max electrical load 500 W for a villa instead of 5-6 kw of electrical heaters